2010 Toyota Camry Intermittent A/C Not Working/Blowing Cold Issue - Fix may apply to many other vehicles

**I had a very intermittent/random “A/C not blowing cold” problem that progressively became worse over a ~6 month period;

When the A/C worked, it was ~40 degrees out the vents. When you least expected it, and needed it, you’d get no cold air.

Solution: Replace the engine intake air filter.

Background on the A/C system:
The 2010 does not have a traditional A/C relay setup, it has a “smart” computer (aka. A/C amplifier) dedicated to the A/C system. It’s buried in the dashboard, so pray it’s not faulty:)

That A/C computer has multiple sensor inputs; using that data it turns the A/C clutch on and off by providing a ground through the board. You’re going to find this hard to believe, but your intermittent A/C may be a dirty air intake filter.

Here’s why:
(Edited to reduce it to layman’s terms as I butchered the technical explanation)

For technical reasons I’ll leave to others, a clogged air filter tricks the A/C computer into shutting off the A/C clutch thinking it’s providing you more power in an acceleration situation.

Changing the air filter fixed the problem for me; how did I figure this out? Totally random. It was time to change the air filter, I removed it, held it to the sun and could barely see any light; held the new one up and the sun blazed through. I was shocked it was so plugged, then I remembered 2023 was very dry and lots of construction was putting insane amounts of dirt in the air.

I hope this helps anyone struggling with an “unfixable/random” Camry A/C issue! Oh, check your cabin filter behind the glove box too!

Another Edit. My Camry has an “A/C amplifier”, computer, that controls the A/C and will shut it off if it “thinks” you’re mashing the pedal.
You can read more about this here: A/C Amplifier HELP! | Tacoma World

Toyota Parts: Air Conditioner Amplifier Assembly #88650-33672 | Autoparts.toyota.com

Must have been way overdue to be changed. The full throttle cut off for the A/C is mostly detected from the throttle position sensor.

Exactly the opposite, wide open throttle decreases the intake vacuum to about zero.

So by that theory the A/C will shut off at idle or somewhere well before full throttle. And if the filter was that clogged there would also be running problems.


Ok, I kinda butchered it. In layman’s terms…the engine is sucking for air the filter can’t provide:)

Yeah, it would. Totally random. Shut of at idle, full speed…you just never knew…but the frequency progressed as the filter became more clogged. In the tanks of gas following the filter replacement, MPG went up.

A Toyota dealer had their fancy computer hooked up and their A/C specialist looking at it and could find nothing wrong with the system. They suggested waiting for total failure. I then just happened to replace the clogged air filter and it hasn’t failed once since, where before it was a real pain.

PS. I replace the air filter annually and have since new in 2010. Tons of very dirty construction plugged it much faster than normal. I’ll be checking it more often if driven through clouds of construction dust in the future.

Butcher? Like hell, you had it totally ass backwards.

1 Like

If you are talking about the engine air filter, I change mine about every 20,000 miles and near looks that bad.

Butcher? Like hell, you had it totally ass backwards.

Lol…yeah, I admit.

Try driving through clouds of construction dust for 6 months and report back…

Yeah the book mentions more often in dusty conditions. I just order two oem filter packages at a time so I have one on the shelf when I want it…

I measure the intake manifold vacuum level as part of routine maintenance. Both at warm idle, and when briefly opening to full throttle. Easy enough to do. By comparing the results over time, this is good way to quickly determine if the engine is misbehaving in a way not yet noticed. Vacuum leaks are particularly vulnerable to being discovered during this test. I discovered a clogged engine air filter one time too.

BTW OP, thanks for taking the time to post how you discovered the cause of you A/C system’s misbehavior. It will show up in the forum history list when folks search for A/C problems, & be helpful to many others. I’m still a bit puzzled why, but since none of my cars have A/C, I don’t really need to know why … lol …

1 Like